The Old Testament is vital to our faith and understanding of God. It makes up 2/3 of the Sacred Text. Yet, John draws a sharp contrast between the Law of Moses and the Law of Christ (John 1:15-24).
Jesus is greater than Moses, who delivered a law that was not able to fulfill the justice of God. Jesus embodies all the wisdom of the Godhead (Colossians 2:9).
Jesus is greater than Elijah, who came to be regarded as the greatest prophet of the Old Testament. He was the one that all the Old Testament prophets up until John had been preparing for (Jon 1:23)!
The Jews held these two men in high esteem, and rightly so. Yet, in Christ, we find, as the name Immanuel implies, God in the flesh.
Jesus was not just a great prophet or even the greatest prophet. He is the focus of all the prophets and the greatest single event in the history of the universe! He is God, our Creator, and our Redeemer!